The new ioctl USBTMC_IOCTL_WRITE sends a generic message to bulk OUT.
This ioctl is used for vendor specific or asynchronous I/O as well.
The message is split into chunks of 4k (page size).
Message size is aligned to 32 bit boundaries.
With flag USBTMC_FLAG_ASYNC the ioctl is non blocking.
With flag USBTMC_FLAG_APPEND additional urbs are queued and
out_status/out_transfer_size is not reset. EPOLLOUT | EPOLLWRNORM
is signaled when all submitted urbs are completed.
Flush flying urbs when file handle is closed or device is
suspended or reset.
Signed-off-by: Guido Kiener <guido.kie...@rohde-schwarz.com>
Reviewed-by: Steve Bayless <steve_bayl...@keysight.com>
---
drivers/usb/class/usbtmc.c | 376 ++++++++++++++++++++++++++++++++++-
include/uapi/linux/usb/tmc.h | 14 ++
2 files changed, 388 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index f5603c835336..b30935d8af6b 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -37,6 +37,8 @@
/* Default USB timeout (in milliseconds) */
#define USBTMC_TIMEOUT 5000
+/* Max number of urbs used in write transfers */
+#define MAX_URBS_IN_FLIGHT 16
/* I/O buffer size used in generic read/write functions */
#define USBTMC_BUFSIZE (4096)
@@ -125,13 +127,24 @@ struct usbtmc_file_data {
u32 timeout;
u8 srq_byte;
atomic_t srq_asserted;
+
u8 eom_val;
u8 term_char;
bool term_char_enabled;
+
+ spinlock_t err_lock; /* lock for errors */
+
+ struct usb_anchor submitted;
+
+ /* data for generic_write */
+ struct semaphore limit_write_sem;
+ u32 out_transfer_size;
+ int out_status;
};
/* Forward declarations */
static struct usb_driver usbtmc_driver;
+static void usbtmc_draw_down(struct usbtmc_file_data *file_data);
static void __user *u64_to_uptr(u64 value)
{
@@ -165,6 +178,10 @@ static int usbtmc_open(struct inode *inode, struct file
*filp)
if (!file_data)
return -ENOMEM;
+ spin_lock_init(&file_data->err_lock);
+ sema_init(&file_data->limit_write_sem, MAX_URBS_IN_FLIGHT);
+ init_usb_anchor(&file_data->submitted);
+
data = usb_get_intfdata(intf);
/* Protect reference to data from file structure until release */
kref_get(&data->kref);
@@ -190,6 +207,36 @@ static int usbtmc_open(struct inode *inode, struct file
*filp)
return 0;
}
+/*
+ * usbtmc_flush - called before file handle is closed
+ */
+static int usbtmc_flush(struct file *file, fl_owner_t id)
+{
+ struct usbtmc_file_data *file_data;
+ struct usbtmc_device_data *data;
+
+ file_data = file->private_data;
+ if (file_data == NULL)
+ return -ENODEV;
+
+ data = file_data->data;
+
+ /* wait for io to stop */
+ mutex_lock(&data->io_mutex);
+
+ usbtmc_draw_down(file_data);
+
+ spin_lock_irq(&file_data->err_lock);
+ file_data->out_status = 0;
+ file_data->out_transfer_size = 0;
+ spin_unlock_irq(&file_data->err_lock);
+
+ wake_up_interruptible_all(&data->waitq);
+ mutex_unlock(&data->io_mutex);
+
+ return 0;
+}
+
static int usbtmc_release(struct inode *inode, struct file *file)
{
struct usbtmc_file_data *file_data = file->private_data;
@@ -622,6 +669,238 @@ static int usbtmc488_ioctl_trigger(struct
usbtmc_file_data *file_data)
return 0;
}
+static struct urb *usbtmc_create_urb(void)
+{
+ const size_t bufsize = USBTMC_BUFSIZE;
+ u8 *dmabuf = NULL;
+ struct urb *urb = usb_alloc_urb(0, GFP_KERNEL);
+
+ if (!urb)
+ return NULL;
+
+ dmabuf = kmalloc(bufsize, GFP_KERNEL);
+ if (!dmabuf) {
+ usb_free_urb(urb);
+ return NULL;
+ }
+
+ urb->transfer_buffer = dmabuf;
+ urb->transfer_buffer_length = bufsize;
+ urb->transfer_flags |= URB_FREE_BUFFER;
+ return urb;
+}
+
+static void usbtmc_write_bulk_cb(struct urb *urb)
+{
+ struct usbtmc_file_data *file_data = urb->context;
+ int wakeup = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&file_data->err_lock, flags);
+ file_data->out_transfer_size += urb->actual_length;
+
+ /* sync/async unlink faults aren't errors */
+ if (urb->status) {
+ if (!(urb->status == -ENOENT ||
+ urb->status == -ECONNRESET ||
+ urb->status == -ESHUTDOWN))
+ dev_err(&file_data->data->intf->dev,
+ "%s - nonzero write bulk status received: %d\n",
+ __func__, urb->status);
+
+ if (!file_data->out_status) {
+ file_data->out_status = urb->status;
+ wakeup = 1;
+ }
+ }
+ spin_unlock_irqrestore(&file_data->err_lock, flags);
+
+ dev_dbg(&file_data->data->intf->dev,
+ "%s - write bulk total size: %u\n",
+ __func__, file_data->out_transfer_size);
+
+ up(&file_data->limit_write_sem);
+ if (usb_anchor_empty(&file_data->submitted) || wakeup)
+ wake_up_interruptible(&file_data->data->waitq);
+}
+
+static ssize_t usbtmc_generic_write(struct usbtmc_file_data *file_data,
+ const void __user *user_buffer,
+ u32 transfer_size,
+ u32 *transferred,
+ u32 flags)
+{
+ struct usbtmc_device_data *data = file_data->data;
+ struct device *dev;
+ u32 done = 0;
+ u32 remaining;
+ unsigned long expire;
+ const u32 bufsize = USBTMC_BUFSIZE;
+ struct urb *urb = NULL;
+ int retval = 0;
+ u32 timeout;
+
+ *transferred = 0;
+
+ /* Get pointer to private data structure */
+ dev = &data->intf->dev;
+
+ dev_dbg(dev, "%s: size=%u flags=0x%X sema=%u\n",
+ __func__, transfer_size, flags,
+ file_data->limit_write_sem.count);
+
+ if (flags & USBTMC_FLAG_APPEND) {
+ spin_lock_irq(&file_data->err_lock);
+ retval = file_data->out_status;
+ spin_unlock_irq(&file_data->err_lock);
+ if (retval < 0)
+ return retval;
+ } else {
+ spin_lock_irq(&file_data->err_lock);
+ file_data->out_transfer_size = 0;
+ file_data->out_status = 0;
+ spin_unlock_irq(&file_data->err_lock);
+ }
+
+ remaining = transfer_size;
+ if (remaining > INT_MAX)
+ remaining = INT_MAX;
+
+ timeout = file_data->timeout;
+ expire = msecs_to_jiffies(timeout);
+
+ while (remaining > 0) {
+ u32 this_part, aligned;
+ u8 *buffer = NULL;
+
+ if (flags & USBTMC_FLAG_ASYNC) {
+ if (down_trylock(&file_data->limit_write_sem)) {
+ retval = (done)?(0):(-EAGAIN);
+ goto exit;
+ }
+ } else {
+ retval = down_timeout(&file_data->limit_write_sem,
+ expire);
+ if (retval < 0) {
+ retval = -ETIMEDOUT;
+ goto error;
+ }
+ }
+
+ spin_lock_irq(&file_data->err_lock);
+ retval = file_data->out_status;
+ spin_unlock_irq(&file_data->err_lock);
+ if (retval < 0) {
+ up(&file_data->limit_write_sem);
+ goto error;
+ }
+
+ /* prepare next urb to send */
+ urb = usbtmc_create_urb();
+ if (!urb) {
+ retval = -ENOMEM;
+ up(&file_data->limit_write_sem);
+ goto error;
+ }
+ buffer = urb->transfer_buffer;
+
+ if (remaining > bufsize)
+ this_part = bufsize;
+ else
+ this_part = remaining;
+
+ if (copy_from_user(buffer, user_buffer + done, this_part)) {
+ retval = -EFAULT;
+ up(&file_data->limit_write_sem);
+ goto error;
+ }
+
+ print_hex_dump_debug("usbtmc ", DUMP_PREFIX_NONE,
+ 16, 1, buffer, this_part, true);
+
+ /* fill bulk with 32 bit alignment to meet USBTMC specification
+ * (size + 3 & ~3) rounds up and simplifies user code
+ */
+ aligned = (this_part + 3) & ~3;
+ dev_dbg(dev, "write(size:%u align:%u done:%u)\n",
+ (unsigned int)this_part,
+ (unsigned int)aligned,
+ (unsigned int)done);
+
+ usb_fill_bulk_urb(urb, data->usb_dev,
+ usb_sndbulkpipe(data->usb_dev, data->bulk_out),
+ urb->transfer_buffer, aligned,
+ usbtmc_write_bulk_cb, file_data);
+
+ usb_anchor_urb(urb, &file_data->submitted);
+ retval = usb_submit_urb(urb, GFP_KERNEL);
+ if (unlikely(retval)) {
+ usb_unanchor_urb(urb);
+ up(&file_data->limit_write_sem);
+ goto error;
+ }
+
+ usb_free_urb(urb);
+ urb = NULL; /* urb will be finally released by usb driver */
+
+ remaining -= this_part;
+ done += this_part;
+ }
+
+ /* All urbs are on the fly */
+ if (!(flags & USBTMC_FLAG_ASYNC)) {
+ if (!usb_wait_anchor_empty_timeout(&file_data->submitted,
+ timeout)) {
+ retval = -ETIMEDOUT;
+ goto error;
+ }
+ }
+
+ retval = 0;
+ goto exit;
+
+error:
+ usb_kill_anchored_urbs(&file_data->submitted);
+exit:
+ usb_free_urb(urb);
+
+ spin_lock_irq(&file_data->err_lock);
+ if (!(flags & USBTMC_FLAG_ASYNC))
+ done = file_data->out_transfer_size;
+ if (!retval && file_data->out_status)
+ retval = file_data->out_status;
+ spin_unlock_irq(&file_data->err_lock);
+
+ *transferred = done;
+
+ dev_dbg(dev, "%s: done=%u, retval=%d, urbstat=%d\n",
+ __func__, done, retval, file_data->out_status);
+
+ return retval;
+}
+
+static ssize_t usbtmc_ioctl_generic_write(struct usbtmc_file_data *file_data,
+ void __user *arg)
+{
+ struct usbtmc_message msg;
+ ssize_t retval = 0;
+
+ /* mutex already locked */
+
+ if (copy_from_user(&msg, arg, sizeof(struct usbtmc_message)))
+ return -EFAULT;
+
+ retval = usbtmc_generic_write(file_data, u64_to_uptr(msg.message),
+ msg.transfer_size, &msg.transferred,
+ msg.flags);
+
+ if (put_user(msg.transferred,
+ &((struct usbtmc_message __user *)arg)->transferred))
+ return -EFAULT;
+
+ return retval;
+}
+
/*
* Sends a REQUEST_DEV_DEP_MSG_IN message on the Bulk-OUT endpoint.
* @transfer_size: number of bytes to request from the device.
@@ -1089,6 +1368,15 @@ static int usbtmc_ioctl_clear_in_halt(struct
usbtmc_device_data *data)
return 0;
}
+static int usbtmc_ioctl_cancel_io(struct usbtmc_file_data *file_data)
+{
+ spin_lock_irq(&file_data->err_lock);
+ file_data->out_status = -ECANCELED;
+ spin_unlock_irq(&file_data->err_lock);
+ usb_kill_anchored_urbs(&file_data->submitted);
+ return 0;
+}
+
static int get_capabilities(struct usbtmc_device_data *data)
{
struct device *dev = &data->usb_dev->dev;
@@ -1463,6 +1751,11 @@ static long usbtmc_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
(void __user *)arg);
break;
+ case USBTMC_IOCTL_WRITE:
+ retval = usbtmc_ioctl_generic_write(file_data,
+ (void __user *)arg);
+ break;
+
case USBTMC488_IOCTL_GET_CAPS:
retval = copy_to_user((void __user *)arg,
&data->usb488_caps,
@@ -1523,7 +1816,19 @@ static __poll_t usbtmc_poll(struct file *file,
poll_table *wait)
poll_wait(file, &data->waitq, wait);
- mask = (atomic_read(&file_data->srq_asserted)) ? EPOLLPRI : 0;
+ mask = 0;
+ if (atomic_read(&file_data->srq_asserted))
+ mask |= EPOLLPRI;
+
+ if (usb_anchor_empty(&file_data->submitted))
+ mask |= (EPOLLOUT | EPOLLWRNORM);
+
+ spin_lock_irq(&file_data->err_lock);
+ if (file_data->out_status)
+ mask |= EPOLLERR;
+ spin_unlock_irq(&file_data->err_lock);
+
+ dev_dbg(&data->intf->dev, "poll mask = %x\n", mask);
no_poll:
mutex_unlock(&data->io_mutex);
@@ -1536,6 +1841,7 @@ static const struct file_operations fops = {
.write = usbtmc_write,
.open = usbtmc_open,
.release = usbtmc_release,
+ .flush = usbtmc_flush,
.unlocked_ioctl = usbtmc_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = usbtmc_ioctl,
@@ -1761,6 +2067,7 @@ static int usbtmc_probe(struct usb_interface *intf,
static void usbtmc_disconnect(struct usb_interface *intf)
{
struct usbtmc_device_data *data = usb_get_intfdata(intf);
+ struct list_head *elem;
usb_deregister_dev(intf, &usbtmc_class);
sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
@@ -1768,14 +2075,46 @@ static void usbtmc_disconnect(struct usb_interface
*intf)
mutex_lock(&data->io_mutex);
data->zombie = 1;
wake_up_interruptible_all(&data->waitq);
+ list_for_each(elem, &data->file_list) {
+ struct usbtmc_file_data *file_data;
+
+ file_data = list_entry(elem,
+ struct usbtmc_file_data,
+ file_elem);
+ usb_kill_anchored_urbs(&file_data->submitted);
+ }
mutex_unlock(&data->io_mutex);
usbtmc_free_int(data);
kref_put(&data->kref, usbtmc_delete);
}
+static void usbtmc_draw_down(struct usbtmc_file_data *file_data)
+{
+ int time;
+
+ time = usb_wait_anchor_empty_timeout(&file_data->submitted, 1000);
+ if (!time)
+ usb_kill_anchored_urbs(&file_data->submitted);
+}
+
static int usbtmc_suspend(struct usb_interface *intf, pm_message_t message)
{
- /* this driver does not have pending URBs */
+ struct usbtmc_device_data *data = usb_get_intfdata(intf);
+ struct list_head *elem;
+
+ if (!data)
+ return 0;
+
+ mutex_lock(&data->io_mutex);
+ list_for_each(elem, &data->file_list) {
+ struct usbtmc_file_data *file_data;
+
+ file_data = list_entry(elem,
+ struct usbtmc_file_data,
+ file_elem);
+ usbtmc_draw_down(file_data);
+ }
+ mutex_unlock(&data->io_mutex);
return 0;
}
@@ -1784,6 +2123,37 @@ static int usbtmc_resume(struct usb_interface *intf)
return 0;
}
+static int usbtmc_pre_reset(struct usb_interface *intf)
+{
+ struct usbtmc_device_data *data = usb_get_intfdata(intf);
+ struct list_head *elem;
+
+ if (!data)
+ return 0;
+
+ mutex_lock(&data->io_mutex);
+
+ list_for_each(elem, &data->file_list) {
+ struct usbtmc_file_data *file_data;
+
+ file_data = list_entry(elem,
+ struct usbtmc_file_data,
+ file_elem);
+ usbtmc_ioctl_cancel_io(file_data);
+ }
+
+ return 0;
+}
+
+static int usbtmc_post_reset(struct usb_interface *intf)
+{
+ struct usbtmc_device_data *data = usb_get_intfdata(intf);
+
+ mutex_unlock(&data->io_mutex);
+
+ return 0;
+}
+
static struct usb_driver usbtmc_driver = {
.name = "usbtmc",
.id_table = usbtmc_devices,
@@ -1791,6 +2161,8 @@ static struct usb_driver usbtmc_driver = {
.disconnect = usbtmc_disconnect,
.suspend = usbtmc_suspend,
.resume = usbtmc_resume,
+ .pre_reset = usbtmc_pre_reset,
+ .post_reset = usbtmc_post_reset,
};
module_usb_driver(usbtmc_driver);
diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
index 95533118ac34..56faeb3b5f0f 100644
--- a/include/uapi/linux/usb/tmc.h
+++ b/include/uapi/linux/usb/tmc.h
@@ -59,6 +59,19 @@ struct usbtmc_termchar {
__u8 term_char_enabled;
} __attribute__ ((packed));
+/*
+ * usbtmc_message->flags:
+ */
+#define USBTMC_FLAG_ASYNC 0x0001
+#define USBTMC_FLAG_APPEND 0x0002
+
+struct usbtmc_message {
+ __u32 transfer_size; /* size of bytes to transfer */
+ __u32 transferred; /* size of received/written bytes */
+ __u32 flags; /* bit 0: 0 = synchronous; 1 = asynchronous */
+ __u64 message; /* pointer to header and data in user space */
+} __attribute__ ((packed));
+
/* Request values for USBTMC driver's ioctl entry point */
#define USBTMC_IOC_NR 91
#define USBTMC_IOCTL_INDICATOR_PULSE _IO(USBTMC_IOC_NR, 1)
@@ -72,6 +85,7 @@ struct usbtmc_termchar {
#define USBTMC_IOCTL_SET_TIMEOUT _IOW(USBTMC_IOC_NR, 10, __u32)
#define USBTMC_IOCTL_EOM_ENABLE _IOW(USBTMC_IOC_NR, 11, __u8)
#define USBTMC_IOCTL_CONFIG_TERMCHAR _IOW(USBTMC_IOC_NR, 12, struct
usbtmc_termchar)
+#define USBTMC_IOCTL_WRITE _IOWR(USBTMC_IOC_NR, 13, struct
usbtmc_message)
#define USBTMC488_IOCTL_GET_CAPS _IOR(USBTMC_IOC_NR, 17, unsigned char)
#define USBTMC488_IOCTL_READ_STB _IOR(USBTMC_IOC_NR, 18, unsigned char)
--
2.17.1
--
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